Burner control apparatus



HQ 5G: AMT-FEM BURNER CONTROL APPARATUS Filed Aug.

Patented .lune 111i 1943 2,322riilli BURNER GCNTYRUL APPARATUS liiienry 1F. iiiery, Milwaukee, Wis., assigner to Miiwaukee Gas Specialty Company, Milwaukee, Wis., a corporation of Wisconsin Application August 3l, i940, Serial No. 354.964

(El. i3d-d) Glaims.

rThis invention relates to burner control apparatus and has to do with a safety shutoff mechanism particularly adapted for use with oil burners, although itmay be used with other burners as suitable or desired.

One of the main objects of the invention is to provide an improved safety shutod mechanism for shutting off the burner upon failure of ignition `or combustion so that the oil or the fuel mixture will not pass into the furnace unignlted where it may become a rer hazard or nood the place where the furnace is located and result in an explosion.

Another object of the invention is to provide an improved thermopile safety shutoff4 for use particularly with oil burners and other equivalent burners.

Another object of the invention is to provide an automatic safety shutoff of relatively simple and inexpensive construction, and which may be installed conveniently and will operate eiectively; also a thermopile safety shutoff having a highly effective arrangement of its thermojunctions and mounted or supported in a highly effective manner.

Further features and advantages of the inven.. tion will be apparent from the following detailed description'taken in connection with the accompam/ing drawing, in which:

Figure l is a diagrammatic illustration of one embodiment of the invention; and

Figure 2 is a fragmentary section through the fuel nozzle shown in Figure l and through the adjacent portionof the furnace, taken substantially on the line 2--2 of Figure 1.

Referring to the drawing, I have shown more or less diagrammatically in Figure 2 the nozzle lli of an oil burner or other equivalent burner which nozzle l@ directs the fuel mixture, for example, of oil and air through an opening ll in the wall l2 of the furnace and into a zone of ignition in the combustion chamber i3.

The oil burner has a motorV and blower (not shown) of any suitable or preferred form for projecting the fuel mixture through the nozzle lli and into the combustion chamber i3.

The fuel mixture is ignited as it leaves the inner end of the nozzle lli by ignition means shown in the form of a spark gap comprising spark gap electrodes lll, l5 connected by conductors it, l'l to the secondary It of a transformer it which transformer is adapted for supplying a high tension spark across the spark gap between the electrodes M, l5 as well understood in the art. A spark plug or 'other suitable ignition means may be employed within the scope of the broader aspects of the present invention.

The primary 22 of the transformer fill is connected to the usual or any suitable line or supply circuit shown generally as comprising line wires 2t, 2d. This line circuit has therein a thermoelectric switch designated in its entirety at and preferably of the type more fully shown and described in the copending. application of Theodore A. Wetzel, Serial No. 148,495, filed June 16, 1937, now Patent No. 2,267,775 dated Dec. 30.

.19t-ll, or of any other suitable or preferred form.

In the illustrated embodiment of the invention, the line wire 2li is connected to a stationary contact 2t at the thermoelectric switch and the other line wire lo is connected at 2li to the switch arm 2li. The thermoelectric switch has an electromagnet comprising a magnet frame 2li and a coll or coil means :it wound or wrapped thereon. The thermoelectric switch is shown as also having an armature 3l shown for purposes of illustration as being carried by and insulated at Bil from the switch arm mi.

The armature ill is mounted for swinging movement preferably on the lower edge of the lower leg of the magnet frame 2a at :it as more fully disclosed in the above-mentioned patent of Theodore A. Wetzel.

The switch arm 2li is preferably held yielding- 1y, for example, by a leaf spring 35, xedly mounted at one end at tt, in `position with the contact im at the outer end of the arm it separated from the contact '2l to open the line circuit 23, Ztl. Upon energizatiqn of the electromagnet, the armature 3l is swung to attracted position about the pivot at :M and the movable contact tu engages the stationary contact 2t to close the line circuit Z3, il.

The motor, shown more or less diagrammatically at l0, is connected in any suitable or preferred manner with the blower or fan (not shown) for projecting the fuel mixture through the nozzle lll and into the combustion chamber i3.

The motor and blower are set into operation when the line circuit 23, 24 is closed by engagement of the contact 38 with the contact 26 as Well understood in the art.

The electromagnet is adapted to be energized, as long as combustion and ignition are functioning properly within the combustion chamber I3, by thermocouple means indicated in its entirely at 45. The thermocouple means 45 ls shown in the form of a thermopile comprising a plurality of pairs of thermocouple elements 46,

41 connected in series as well understood in the art. The two elements t6, Al of each thermocouple forming the thermopile 45 are of different thermoelectric characteristics.

One suitable form of mounting for the thermopile 45 is shown as comprising an insulating sleeve 50 mounted and suitably held in place upon the exterior of the nozzle i near the inner end thereof. The thermopile elements t6, all are shown as carried by and extending through the sleeve 50. The Outer ends of the thermopile elements are `ioined together to form the cold thermojunctions 52 of the thermopile. The inner ends of the thermopile elements t6, all4 which are shown as converging inwardly extend into the combustion chamber it and are joined to form the hot thermojunctions M. These hot thermojunctions iii are arranged in circumferentially spaced relation about an extension of the axis of the nozzle lll and in position to be heated by the combustion of the fuel in the zone of ignition within the combustion chamber I3 as long as combustion and ignition are functioning properly. The insulating sleeve 5D is shown as having circumferentially spaced openings 5t for the passage of adequate air therethrough in the direction indicated by the arrows in Figure 2.

An outer nozzle part 58 may be mounted and held in place upon the exterior of the sleeve tit. This outer nozzle part encloses and protects the thermopile or thermocouple elements dit, #il and extends through the opening Il in the furnace wall and into the combustion chamber I3. The wall of the nozzle part 5B is shown as sloping or converging to a reduced diameter at its inner end and this inner end of the nozzle part tu is shown as terminating short of the hot junctions of the thermopile. The spark gap electrodes It, l5 are also shown as carried by the insulating sleeve 50 and extending through the space between the nozzle ill and the nozzle part 5B to dispose the inner spark gap ends in suitable position.

The outer end or terminal of the thermopile r thermocouple element 46' is connected by a conductor 62 to one terminal of the coil or .coil means 30 of the-electromagnet. The other terminal of the coil or coil means 30 is connected by a conductor 64 to the outer end or terminal of the thermocouple or thermopile element M'.

The operation of the apparatus is asfollows:

Assuming that ignition and combustion of the fuel mixture are functioning properly Within the combustion chamber i3, the combustion of the fuel heats the "hot Junctions 54 of the thermopile 45 to set up the thermoelectric current which energizes the eiectromagnet and actuates the armature 32 to and holds same in attracted position engaging the contact 38 with the contact 25 and maintaining this engagement as long as proper ignition and combustion is taking place. When the line circuit 23, 2| is thus closed and as long as it remains closed, the motor I0 and blower or fan operate to project the fuel mixture into the combustion chamber. The spark gap means I4, I functions through the secondary circuit I6, Il to produce the spark for ignition of the fuel.

If, for any reason, ignition fails or the proper combustion of the fuel for heating the thermojunctions it does not take place, the discontinuance or reduction of the thermoelectric current results in deenergization of the electromagnet and the armature 32 is swung to retracted position in a clockwise direction (Figure 1) about astratto its pivot 3l and in the illustrated embodiment of the invention under the action of the spring 35. This separates the contact 3B from the contact 26 opening the line circuit 23, 2d and stopping the operation of the motor 40 and its blower or fan and thereby the injection of further fuel into the combustion chamber i3.

Manual or other means may be provided for closing the line circuit 23, 24 for example at the thermoelectric switch or elsewhere as desired when the ignition or other means is again rendered operative and this means may be adapted to be released when the combustion of the fuel again heats the thermojunctions El to energize the electromagnet and maintain the armature 32 in attracted position and the switch closed. Of course, the thermoelectric switch may be closed merely by the application of heat to the thermojunctions 5d to energize the electromagnet sumciently to actuate the armature l2 to attracted positiont The embodiment of the invention shown in the drawing is for illustrative purposes only and it is to be expressly understood that said drawing and the accompanying specification are not to be construed as a definition of the limits or scope of the invention, reference being had to the appended claims for that purpose.

I claim:

1. In combination., a fuel supply nozzle, an insulating sleeve surrounding and carried on the external surface of said nozzle, a thermopile comprising a plurality of pairs of thermocouple elements extending through and carried by said sleeve with their outer ends joined together, the inner ends of said thermocouple elements extending from the inner end of said nozzle and joined to form hot" thermojunctions in eircumferentially spaced relation beyond the inner end of said nozzle, an outer nozzle part surrounding and held in place on the external surface of said insulating sleeve, said outer nozzle part enclosing and protecting the thermocouple elements and terminating short of said ho thermojunctions and a pair of spark gap electrodes carried by said insulating sleeve and extending between the fuel supply nozzle and the outer nozzle part with the ends thereof disposed inwardly beyond the fuel supply nozzle and forming a spark gap for igniting the fuel.

2. In combination, a fuel supply nozzle, an insulating sleeve surrounding and carried on the external surface of said nozzle, a thermopile comprising a plurality of pairs of thermocouple elements extending through and carried by said sleeve with their outer ends joined together, the inner ends of said thermocouple elements extending from the inner end of said nozzle and joined to form hot thermojunctions in circumferentially spaced relation beyond the inner end of said nozzle, an outer nozzle part surrounding and held in place on the external surface of said insulating seeve, said outer nozzle part enclosing and protecting the thermocouple elements and terminating short of said hot thermojunctions and a pair of spark gap electrodes carried by said insulating sleeve and extending between the fuel supply nozzle'and the outer nozzle part with the vends thereof disposed inwardly beyond the fuel supply nozzle and forming a spark gap for igniting the fuel, said insulating sleeve having circumferentially spaced openings for the passage of air therethrough.

3. In combination, a fuel supply nozzle, an

aeaaeio by said sleeve 'with their outer ends joined togather, the inner ends of said thermocouple elements extending from the inner end of said nozzle and joined to form hot thermojunc` tions in circumferentially spaced relation beyond the inner end of said nozzle, the outer ends of said thermocouple elements being joined together to form cold thermojunctions adjacent the outer end of said insulating sleeve, said insulating sleeve having circumferentially spaced openings extending through the sleeve between said thermocouple elements `for the passage of air therethrough and adjacent said cold" thermojunctions. l y' a. In combination, a fuel supply nozzle, van insulating sleeve surrounding and carried on the external surface ot said nozzle. a thermopile comprising a plurality of pairs oi thermocouple elernents extending through and carried by said sleeve with their outer ends joined together,

lthe inner ends of said thermocouple elements cumferentially spaced relation beyond the inner end oi said nozzle, the outer ends of said thermocouple elements being joined together to .form

,"cold thermojunctions adjacent the outer end of said insulating sleeve, said insulating sleeve having ciroumferentially spaced openings extending through the sleeve between said thermo# couple elements for the passage of air therethrough and adjacent said eold" thermojunctions, and an outer nozzle .part surrounding and held in place on the external'surface oi said insulating sleeve, saidouter nozzle part enclosing and protecting the thermoeouple elements and terminating short or said Inot thermojunctions.

5. In combination, a fuel supply nozzle, an i insulating sleeve surrounding and carriedon the external surface of said nozzle, a thermopile comprising a plurality of pairs of thermocouple elements extending through and carried by said insulating sleeve with their outer ends joined together, the inner ends of said thermocouple elements extending from the inner end of said nozzle and joined to form hot thermojunctions in `circumferentially spaced relation beyond the inner end of said nozzlel and a pair of spark gap electrodes carried by said insulating sleeve and extending to position with the ends thereof disposed inwardly beyond the fuel supply nozzle and forming a spark gap for igniting the fuel.

. HENRY F. ALFERY. 

